Ciphering and deciphering mechanism



April 25,1939. R. o. SALMON CIPHERINCY AND DECIPHERING MECHANISM 2 SheetsSheet 1 Filed July 11, 1935 ggwmm 6e Patented A r. 25, 1939 UNITED STATES 2,155,097 CIPBERING AND nnclrimnme MECHANISM Reginald Dennis Salmon, Croydon, England, as-

don, England signor to Creed and Oompany, Limited, Croy- Application July 11, 1935, Serial No, 30,852

In Great Britain August 1'1, 1934 18 Claims.

According to one feature of this invention the successive characters of a message are displaced by different amounts in an alphabetical scale as determined by a set of coding characters each consisting of a plurality of elements, the separate elements being read. by corresponding feelers. The coding characters may, for example, be

represented according to the well known ilve" unit code as used in telegraph'y and be read by peckers in the manner usual in telegraphtransmitters controlled by a perforated tape. The ac:- tion of each pecker in being permitted to rise through a'perforation in the tape or in bein prevented from so doing may then be transferred to an indicating member in such a manner that the movement of the latter is:--the aggregate of the movement determined by all the peckers. each pecker controlling a particular degree of movement of the indicating member. For example, in the case in which the indicating member is rotary, one pecker determines one half a revolution', the next pecker, one quarter and so on.

As will be explained hereafter it is of importance for certain purposes that the maximum displacement in the alphabetical scale that. a character can receive be less than 26 places, and

.. it would be preferable therefore that the code ments of the coding characters as projections or depressions'on a series of discs, there being one disc for each element in the character. Each disc has a different number of elements thereon and for this purpose the discs are of different diameters. They are however arranged so that their circumferences are level at one portion so that levers one for each disc may there be controlled according to the projections and depressions; These levers may then determine the aggregate motion of the indicating member in the manner explained above for the peckers.

It is a feature of this invention that the amount of displacement in an alphabetical scale of successive characters of amessage is determined by an element of a coding character of a set of coding characters. r

According to another feature of this invention an indicating member is moved in accordance with each character of a message and also in accordance with successive characters of a set of coding characters each consisting of a plurality of elements, and in which the motion given to the indicating member by each coding-character is theaggregate of a series of separate motions given by the separate elements.

The motion given to the indicating member for each character of the message may itself be the aggregate of amounts of motion determined by the separate elements of a telegraphic code representing such character. In this way the in:- vention is particularly suitable for the telegraphic transmission of a ciphered message and its automatic decipherment at the receiving end.

The preferred embodiment of the invention is ,shown in the accompanying drawings in which Fig. 1 'is a diagrammatic elevation and Fig. 2 a diagrammatic plan of a ciphering apparatus adapted to print a ciphered message and to be described hereinin Fig. 1. The outer periphery of each ring is cut to form projections and depressions as shown. The rings are driven so that their surface speeds are equal and for each character to be ciphered ordeciphered the circumference of each ring moves through the same distance. The projections and depressions are equal to this distance or to integral multiples thereof. The rings are of different sizes so that the number of these elementary distances around the circumference of each ring is different and is equal to. a prime number, for example, 53, 51, 59 and 6|. The rings are rotated by a gear wheel 10 engaging their inner peripheries through the space of one element at each step. Gear wheel 10 may be driven by any suitable means in timed relation with a part of the printing apparatus so as to move gear 10 one tooth for each letter'sp acing movement of the printing apparatus.

It is a feature of this invention to provide a number of annular rings upon the outer. circumferences of which are arranged elements which jointly determine the displacement in an alphabetical scale to be given to the character of a message and upon the inner circumferences of which are arranged gear teeth for rotating the rings.

By means of this feature the rings may be readily disengaged by hand from their driving means and turned to any convenient, agreed, position for the commencement of ciphering or decipher ing operations.

For each character there is a different combination of projections and depressions along the line at the top touching all four rings. This combination can be considered as representing a character in a telegraphic code, projections being regarded as marking elements and depressions as spacing elements or vice versa. With four rings the total number of combinations is l6 but the total number of combinations that will be set up before the cycle is repeated and before the combinations are again set up in the same order may,

' by suitable arrangementof the elements be the product of the numbers of elements in the circumferences of the several discs, or, in the example given above, the product of 53, 51, 59 and BI, i. e. approximately 10.8 x 10.

The combinations that are set up are read off by four pivoted levers 2| which control four respective rocking arms l9. Each arm l9 controls two cam levers 25 and 21, each provided with a slot permitting movement on a corresponding pin, saidarms being adapted to hold the upper end of one or the other of said levers so that lateral movement on said pins is prevented acoordingly as the corresponding lever 2| is held on the top of a projection or allowed to fall into a depression on the circumference of the cor-4 responding ring 22. All the came levers bear upon respective cams on a cam sleeve. This cam sleeve carries a detent cam 20 with which a pawl 26 engages. This pawl is withdrawn for each character to allow the cam sleeve to make one revolution only, in a manner Well known in the art of printing telegraphy. An example of one form of such an arrangement is illustrated in the patent to R. G. Griflith #1,921,40'7, issued-August 8, 1933, at 3'! in the drawings.

The cam sleeve acts upon the four pairs of levers 25 and 21. The levers which are held at the top end move four corresponding bars 24 accordingly, the other levers moving idly' at their upper ends an amount determined by the slots.

Each of the bars 25 if it moves from the position in which it was previously left controls by its movement a pair of, levers l2, l4 acting upon a detent cam l3 to allow it to rotate for half a revolution. The half revolution of cam I3 moves a lever 38 in one direction or the other. Each liver 38 carries a gear segment on one end which a ts on a gear wheel to which is attached a planet wheel 48 (Fig. 2) meshing with inner and outer sun members. Each planet wheel 48 with its inner and outer sun members forms a gear unit. The inner sun member of an end gear unit is fixed, the outer sun member of that gear unit is attached tothe inner sun member of the next gear unit. The outer-sun member of this latter gear unit is attached to the inner sun member of the next gear unit and so on. Finally the outer sun member 49 of the last gear unit moves a shaft 5|, which, through gear wheels 52A and 52 moves a shaft to one end of which is fixed a type wheel 55 from which a ciphered or deciphered character may be printed. The mechanism for moving the type wheel 55 according to the movemerits of the rods 24 is similar to that described in British patent to R. G. Grifi'ith, Serial No. 436,296. As shown in Fig. 2 the aggregate movement mechanism includes only four units since only four control bars 24 are used. The complete details of the structure are readily obtainable from my above mentioned British patent and since these details are not a part of my present invention the apparatus as shown in the drawings is largely diagrammatic.

Other forms of aggregate motion'devices may also be used as for example, that described in my prior United States Patent, Serial No. 2,093,873, issued Sept. 21, 1937 or that described in co- I pending application Ser. No. 33,545.

The type wheel 55 is also rotated according to the character in clear in the case of ciphering or according to the character in cipher in the case of deciphering as will be hereinafter described.

In the apparatus shown the typewheel 55 is rotated in accordance with the character denoted by a depressed'key.

A keyboard of the kind usually employed in start stop printing telegraphs, for example as illustrated in Patent .9 7, s provided and each key when depressed moves in the usual way,

five bars to right .or left in a particular combi-.

nation depending on the depressed key, together with a universal bar, which determines the starting into rotation for' one revolution of a cam shaft which, in any usual manner controls the stepping of the various tapes upon which characters are printed with modifications to be hereinafter described, and also controls the stepping of the rings 22.

The five combination bars move, through levers l, five bars 2, each of which determines the movement of corresponding detents 3 and 5 engaging an eccentric cam 4. Movement of a bar 2 from the position in which it was left releases its cam 4 for half a revolution. The cams 4 control levers W, gear segments on which engage with gears 60. On each gear 60 is fixed an arm carrying a planet wheel 59 meshing with inner and outer sun members A and 4:5. This forms a gear unit, and the gear units are interconnected in the manner explained above with reference to the gear units moved by levers 38. In this case however there are five, gear units. The movements imparted to all the gear units are added together and transmitted to spindle 58. The gear ratios are so chosen that if the planet wheel is held stationary the ratio of the movement of the outer sun wheel to that of the inner wheel is 2 to 1. Thus if the first gear unit rotates shaft 55 thorugh half a revolution, the

next will rotate it through a quarter revolution, and so on, the last rotating it through I}; revolution. This aggregate motion mechanism as shown is also of the same form as illustrated in my British Patent 436,296.

The shaft 58 drives through intermediate gear 51 the gear 54 which is on a sleeve carrying a type wheel 46 and cams 40 and 50. On this sleeve is also a bevel gear 55A meshing with planet gear wheel 56, which in turn meshes with bevel gear 53 which drives the shaft upon which is typewheel 55. The planet wheel 56 is carried by the gear 52 driven by the ciphering apparatus as explained above. Typewheel 55 is thus given a motion which is the aggregate of that due to the different elements in the telegraphic code represented by movement of the bars 2 and of that due to the different elements of the character represented by the projections and depressions presented to the four feelers 2|.

The type wheel 56 has two rows of characters from which the ciphered message is typed con tains only letters. In order to be able to encipher a message containing figures, two letters are taken as shift signals. It is proposed to use letters J and Z for figure and letter shiftrespectively, and these letters will therefore be left of! typewheel 46, but not off typewheel 55. If letter J is depressed on the keyboard, it indicates that the following characters are to be taken as figures, and if letter Z, that the following characters are to be taken as letters. Cam 40 on the same sleeve as typewheel 46 is provided with a notch 9 (Fig. 1) and levers 8, l0 feel for the position of this notch. For each key depressed, cam 6 is allowed to rotate for one revolution through suitable connection with the regular printer cam. (notlshown). and allows lever I to'release the two-levers 6, II to feel for the position of the notch 9. If either the position of letter J or of letter Z has been selected lever ll. or lever ill respectively will fall into the notch and rod 39 is moved to the left or the right. Two printing hammers I I, 12 one to strike against the letters and one "against the figures are fixed on a shaft 13 carriedin a frame 43 and having a depending portion 4| engaged by rod 39. When rod 39 is moved to the left hammer II is rotated away from the printing position and hammer 12, which is opposite the figures, into printing position. i v

The figure and letter shifts will of course ciphered like any other letters and the corresponding enciphered character will be printed from wheel 55. It will of course be necessary not to use the two letters allotted to the two shift positions as letters in the message. This presents no difiiculty as regards the letters J and Z in the English language, as these letters can be replaced by others whilst leaving the sense perfectly clear. For messages in other languages it may be necessary to choose another two letters which can be reaklily dispensed with. If it is desired to produce in typed form a message in cipher that will be accepted for transmission by cable companies it is important that the cipher shall contain letters only. The cipher text is therefore limited to 26 characters. A

, space between words as denoted by the depression of the space bar on the keyboard is ciphered by this machine as if it were a character. As the number of characters on typewheel 65 is limited to 26, and as a space in the message to be ciphered would be a character additional to the 26, a letter of the alphabet must be used for the purpose and it is proposed to use X. Depression of the space key on the keyboard then determines the rotation of typewheel 46 to letter x where a space is left, and also typewheel 55 to letter K. The

' latter typewheel is, however, rotated in additionin accordance with the ciphering mechanism. It will,-of course, be necessary to replace the letter X, when it occurs in the actual textof-the'mesthat will be accepted for transmission by cable companies, the letters must bedivided into groups of five. For this purpose a space must be inserted after every five letters. This is accomplished by the arrangement shown in Fig. 3.

The tape upon which'typewheel 55 prints is stepped by the ratchet wheel shown, which is acted on by the pawl 62 operated by the regular printer cam released for rotation by the universal bar on the keyboard. This pawl is arranged so that at each movement it would be'capable of being drawn back over the space of 2 teeth of the ratchet wheel, if it were not forthe stop on lever 6|. Lever 6| is held by a spring against the cam 65 shown in Fig. 3, which cam rotates with the ratchet wheel. For ordinary letters, therefore, the pawl 62 is withdrawn only the space of one tooth and the ratchet wheel is then, on reengagement of the pawl, stepped the distance of one tooth. After every five teeth, a hump on the cam 65 pushes lever 6| away from pawl 62 and allows it to be withdrawn the space of two teeth. The ratchet wheel is then stepped the space of V not be displaced by the ciphering mechanism 7 through more than its own circumference.

In producing a ciphered message in typed form two teeth. The lever 6| when moved by the cam shown also actuates a locking bar on the printer, which in well known manner locks the keys of the keyboard against depression until the lever 6| has returned to normal.

For the purpose of allowing part of the message to be typed in clear and part in cipher, two characters of the upper case are allotted to cause the change over. The rod 39, which is moved by levers 8 and ID as previously described, controls a lever II and when rod 39 is in letter shift posi-- tion commonly termed the lower case position lever engages a rod 31, as shown in Fig, 1 and prevents it from moving. When rod 39 is in the figure shift position or upper case position, the lever II is raised from engagement with rod 31-, which is free to move. The rod 31 is controlled by two levers similar to levers 8 and I0, actuated by cam 5|] (Fig. 2) which has a notch therein like notch 9 in cam 40. This notch is,'however,

in the position corresponding toletters F and H on type wheel46. When letter F in the upper case is pressed, therefore, rod 31 is moved to the left.

This moves bell crank lever IS on its pivot so that a pin i6 thereon moves the lever carrying the pawl 26 at one end and a hook l1 at the other.

end so as to remove the hook H- from engagement with a lever 36 and allow a lever carrying a detent 34 and hook l6 to move under action of some means, such as a spring (not shown) until hook l6 engages lever 36. The lever 36 is moved by the ,regular printer cam released for one revolution for each key depressed so that when it engages with hook "5 the pawl 34 release a detent cam 3| for one revolution for each key depressed. Cam

9| is on a sleeve having four cams controlling four pairs of levers such as 28 and 29. Pins on, the

lower ends of these levers engage projections on the underside of bars 24 used for ciphering purposes. The fiour pairs of levers suchas 28 and 29 move the rods-24 that have been displaced back into normal position. i The ciphering mechanism is thus out of'action and, moreover, the gear wheel 52A has been restored to' original position by the return of rods 24 to their normal position. so that it gives no displacement to type wheel 55A. The letter shift key of the printer must, now, be depressedand subsequent printing from typewheel 55 is in clear.

When the key J for fiure shift is depressed,

lever ll re-engages rod 31 and if key H is now depressed, (or the key for H in the upper case if separate sets of lower and upper case keys are provided) rod 31 is moved to the right, pin l8 removes hook I6 from engagement with lever 36 and allows hook I! to re-engage therewith. The ciphering mechanism is then again in action.

It should be noted thatfigures and letters are shown on typewheel 46 only for the purpose of illustrating the relative positions from which printing takes place after figure and letter shift keys have been depressed. The figures arejnot in practice arranged opposite the respective letters shown and the upper case positions corresponding to letters F and H are blank. The combinations representing these two letters in the upper case are not in ordinary telegraph practice, allotted to any figure or operation.

In order that messages may be despatched telegraphically a cam drum 64 is provided on the same shaft as typewheel 55. This cam drum has cut on its circumference representations in a telegraphic code of the characters on typewheel 55, and in corresponding places. If the code be the five unit code, it may be read by feelers in the same manner as the notches and depressions on rings 22 are read by feelers 2|, and these feelers may actuate rods 63 in the same manner as rods 24 are actuated. A space after every five letters may then be inserted by causing the lever 6|, Fig. 3, to act on the under side of all the bars 63 and restore them to spacing position. The bars 63 may control a punch block to perforate a tape for subsequent transmission of the message, or

may control a transmitter inexactly the same manner as the permutation bars in an ordinary keyboard transmitter. a The machine as so far described is not reversible so that a message, type on the keys in cipher would not be reproduced in clear. In the deciphering machine it is necessary that the gear wheel 52A should give the reverse rot'ation to gear wheel 52 from that given in the ciphering maof a plurality of elements for determining the amount of said displacement, and feelers cooperating with said elements for effecting said displacement.

2. Ciphering or deciphering apparatus in which the amounts of displacement in an alphabetical scale of successive characters of a message is determined by the motion of a device, comprising. a coding means consisting of a set of coding 'elements, means under control of each coding element to impart separate motions to said device, and to move said device a total amount dependent upon the aggregate of said separate motions.

3. Ciphering or deciphering apparatus as claimed in claim 1 in which the elements of a set of coding means for determining successive displacements in an alphabetical scale of the characters of a message are constituted by notches and depressions on the circumferences of a plurality of rings, there being a prime number of elements on the circumference of each ring, and in which means is provided for rotating each ring through an integral number of elements for each character of the message. I

4. Ciphering or deciphering apparatus comprising a plurality of rings of different diameters the circumferences of which are divided into elements of two different kinds, the total number of elements in the circumference of each ring being a prime number, means for rotating all the rings through the space of one or more elements for each character to be ciphered or deciphered, and means for determining a displacement in an alphabetical scale of a character of the message depending upon the combination of elements, one for each ring, presented simultaneously to a corresponding number 01' feelers.

' 5. Ciphering or deciphering apparatus as claimed in claim 4 in which the said rings are formed as annuli having the coding elements on their outer circumferences and gear teeth for driving them on their inner circumferences.

6. Ciphering or deciphering apparatus comprising a type wheel, a keyboard, permutation bars moved in various combinations by the depression of keys of the keyboard, a ciphering mechanism comprising a second set of permutation bars moved in various combinations according to a coding means, and an aggregate motion device for imparting to said type wheel. a movement determined by the movement of all the said permutation bars.

'7. Ciphering or deciphering apparatus as claimed in claim 6 in which the said aggregate motion device consists of two separate aggregate motion devices-forgiving a movement to said.

type wheel according to the respective sets of permutation bars, together with gearing aggregating the motion of both devices.

8. Ciphering apparatus as claimed in claim 1 further comprising means for typing a ciphered character corresponding to each character and each space of a message in clear and means for automatically inserting a space after every five characters.

9. Ciphering apparatus as claimed in claim 1 further comprising means for automatically inserting a space after every five characters.

' 10. Apparatus as claimed in claim 6 in which the said aggregate motion device consists of two separate aggregate motion devices, for giving a movement; to said type Wheel according to the respective sets of permutation bars, together with gearing aggregating the motion of both' devices, and a type wheel moved only by said first set'of permutation bars, from which tvpewheel the message may be printed directly.

11. Apparatus as claimed in claim 6 in which the said aggregate motion device consists of two separate aggregate motion devices, for givinga movement to said type wheel according to the respective sets of permutation bars, together with gearing aggregating the motion of both devices. and means actuated by the aggregate motion device moved by the permutation bars'of the keyboard for restoring the other aggregate motion device to initial position and for putting the ciphering mechanism out of action.

12. Ciphering or deciphering apparatt as claimed in claim 1 in which the elements constituting said coding means mechanically control the movementof said feelers, and means under control of the movement of said feelers to control the position of an indicating member.

13. Ciphering or deciphering apparatus as claimed in claim 1 in which means are provided under control of said feelers to control the position of an indicating member.

14. Ciphering or deciphering apparatus as claimed in claim 2 further comprisingatype wheel, and means for moving said type wheel in accordance with each element of said coding means and in accordance with a character of said message.

15. Ciphering or deciphering apparatus comprising an indicating member, means for moving said indicating member in accordance with each character ofa message and also in accordance with successive characters determined by a set of coding means, said set of coding means consisting of a plurality of elements for producing separate motions, and means whereby the motion given to said indicating member by each successive character is the-aggregate of a series 01 separate motions given by said separate elements.

16. Ciphering or deciphering apparatus as claimed in claim 15 further comprising means under control of the separate elements of a telegraphic code combination, representing each character of a message for determining the successive characters determined by, said coding means.

17. In ciphering or deciphering apparatus a plurality of annular discs, and elements for jointly determining the displacement in an alphabetical scale to be given to the character of a message arranged on the outer circumference of said,

discs and gear teeth upon the inner circumference of said'discs for rotating said discs.

18. Ciphering or deciphering apparatus as claimed in claim 1 further comprising rods movable in one or the other of two directions under control of said feelers, an indicating memer, an aggregate motion device for controlling said indicating member, and means actuated by move ment of said rods for controlling said aggregate motion device.

REGINALD DENNIS SALMON. 

